From [ http://clojure.blip.tv/file/1313398/ ] I got the impression that Clojure on the CLR was back-burner at best. There appears to be only one committer to the CLR source base since February (possibly longer).
I believe the greater push is to write Clojure in Clojure which will (hopefully) facilitate targetting other platforms.
http://blog.n01se.net/?p=41
http://clojure.org/todo
As a rule, things move pretty fast in Clojure-land. And in the beginning it was dual-platform, so it's not really a new idea either.